iphone - 如何逐渐减慢旋转动画

Question

我正在开发一个轮盘赌应用程序。其中，如果我点击中心按钮，轮子应该旋转几秒钟，然后它的速度应该逐渐变慢。如果有人知道，请以正确的方式指导我。

我可以以一定的速度旋转 imageView，但我很难逐渐降低轮子的速度。

旋转代码

CALayer *layer = container.layer;
CAKeyframeAnimation *animation;
animation = [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"];
animation.duration = 1.5f;
animation.cumulative = YES;
animation.repeatCount = 1;
animation.values = [NSArray arrayWithObjects:       // i.e., Rotation values for the 3 keyframes, in RADIANS
                    [NSNumber numberWithFloat:0.0 * M_PI],
                    [NSNumber numberWithFloat:0.75 * M_PI],
                    [NSNumber numberWithFloat:1.5 * M_PI], nil];
animation.keyTimes = [NSArray arrayWithObjects:     // Relative timing values for the 3 keyframes
                      [NSNumber numberWithFloat:0],
                      [NSNumber numberWithFloat:.5],
                      [NSNumber numberWithFloat:1.0], nil];
animation.timingFunctions = [NSArray arrayWithObjects:
                             [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn], // from keyframe 1 to keyframe 2
                             [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut], nil];  // from keyframe 2 to keyframe 3
animation.removedOnCompletion = NO;
animation.fillMode = kCAFillModeForwards;
[layer addAnimation:animation forKey:nil];

Answer 1

查看 CAKeyframeAnimation 的文档，您可以使用 timingFunctions 属性来添加缓动等

https://developer.apple.com/library/mac/#documentation/GraphicsImaging/Reference/CAKeyframeAnimation_class/Introduction/Introduction.html